Wow, not a single reply?!
I am disappointed....but I did find another way.
I had our civil engineer export their Civil 3D to AutoCAD as a surface with faces. That AutoCAD export created contiguous contour lines which were exactly what I needed; they imported to scale, at the correct elevations and survey point. I'm surprised after 72 views...not a single comment?!

I cant stipulate why others havent responded, but... In Short: I stopped messing with DWG's from Civil, because the entire workflow (and output) from Revit is pretty crap, using the Topo tool. So , since i dont bother using pop much, i dont bother cleaning up Civils file. And since i dont bother cleaning it up, didnt have any great advice to give?

I use Shape Edited Roofs for Topo, so you cant *auto import* anyway.

Commentary

TRW,
If I can avoid working with site plans in Revit I do...but this was a campus master planning that we were requested to execute completely in Revit.
I'm glad I actually found a solution online that discussed the difficulties between coordinating between Civil 3D and Revit. IT works for me for this project.
Thanks for the comment though....just surprised that over 70 views occurred and not a peep;>

Didn't see your post until now.

The gaps in contours don't seriously alter Revit's ability to create a toposurface. Revit systematically applies points at each end of and along each line segment for the elements it finds assigned to the layers we specify while creating the surface. It is important to know exactly which layers are appropriate to choose to create the surface, naturally. If not the surface is created based on things that don't define the contours of the surface.

I don't advise altering a source Civil File except to sort out what is required to get a decent result. That usually means opening the file and inspecting the layer structure, checking how the contours are defined (lines, polylines, AEC Contours etc.). Revit doesn't have a "point" element so it doesn't recognize them in DWG files either. Whatever I end up doing I then tell the civil consultant what I did so they can take it into account and consider doing if they send a revision later.

You can also create several surfaces from different layers of elements in the file and then merge them within Revit to create the final surface. It can take some experimentation. If a contour at 170 for example has a segment that isn't at the correct elevation then that will create points at that incorrect elevation and you'll see some extravagant jagged surface triangulation. It's easy to fix though, select the points and assign them to the correct elevation or delete them and add them manually later.

I did not see your post either until now.

As you discovered, one of the better ways is to produce your surface using civil 3D if you have access to it, and then use that in revit to complete the topo creation.

As with all things, it dépends on your source, if the source file is poorly done then it makes life complicated in revit, this isn't really a shortfall of revit or a problem of revit, its your source file that hasnt been done properly or was done on a tighter budget and therefore contains less information.

Contours are one of the worst ways to create topo in revit, you are better off using a triangulated surface (which you can create in civil 3D using the cad file usually) Contours don't contain certain things and this is where my technical vocabulary is getting lost because I have learned many of the terms in my local french speaking region (lignes de scission) for example. Ex. I have a path crossing my contours, unless I have a triangulated surface between the 5cm difference between my path, and my contour in elevation, then I wont see this feature in my topo. If I have a complete and well done Survey file I can see very fine detail of features and existing structure, roadways and paths, gutters, stairs, etc in my topo file. The better your source file is, the more detail you will see, and contours simply dont have this information. So always use a triangulated surface - if you can get it. Its just more détailed and more accurate.

As for revit being poor topo Tools - well yes and no.
First off, its not a civil design tool, so its not intended to create detailed topo plans - use the right tool for the job, civil 3D is made for this.
I personally use a 3 point workflow between infraworks, civil 3d and Revit. As they are all Autodesk products they tend to speak nicely with each other. Also, sometimes I use 3DS Max to import building geometry also. In infraworks I can start with a bing map (20cm accuracy) and bring in all my public source documents to bring up the level of detail, and if I have a detailed publicly available satelleite Survey, I can get to 5cm precision (I can literally read numberplates on cars in the images). I can then bring this in through civil 3D and I have a perfect topo surface in revit to very high precision, including tunnels, bridges, buildings and roadways, piping, cables etc etc. In addition I can keep road names etc straight out of the bing maps.

Revit does this just fine, but revit shows the RESULT it is not made to create modifications.

Yeah, I missed the post too...been a bit busy with submittals this week.

If you are going to use the Revit Topography tool, don't try to do the entire site as one big object, it just won't work. Don't be afraid to break up the topography at buildings and roads. Small areas, such as islands, i use Aaron's approach with roofs as it is just easier to manipulate. Same thing with roads and parking lots as sweeps just work better on a roof vs a floor object.

What I usually do is build the existing topo first...then create the roads, sidewalks, building pads, retaining walls, etc. first then I fill it in with the new topography from what the civil side designs.

If you are planning on creating sections you will be adding an earth fill pattern, it's not going to be perfect right away. Keep it schematic looking though, the site model shouldn't be used for CD level docs. Floor heights can be right on, but the earthwork around the building wont be.

Presentation wise...it's probably better to load the Revit model into Infraworks and do all the grading in Civil3D and load it back into Infraworks as Karalon mentioned. Our office is trying to get more into Infraworks as we are 98% Civil... I'm the only architecture tech, and they could care less about my Revit models as they can build simple buildings themselves in Civil3D.

Thanks to everybody who chimed in. I've finally worked out a decent toposurface for general modeling. It's main purpose was to give us (and the client) a better idea of the relationships between the many campus buildings and the sloped site (60 foot grade change). It also allowed me to get realistic site sections to determine the height relationships. I do not think it is a great tool for creating solid site plans, so civil usually takes care of the bulk of that for us.
Thanks again.

Anyone know what the recently released Revit 2019 add-in for Infraworks does?

I can see it in my menu bar and I can download models in Infraworks which people variously use other programs to intermediate into Revit but it would be nice if Revit talked nicely to Infraworks

You have always been able to import a Revit model into Infraworks.... But there was supposed to be a way to get a Civil 3D and I think Infraworks model into Revit...as you can manipulate a Civil 3D model in Infraworks then save it back to Civil 3D.